Vehicle wheel comprising a drive device and a braking device

Abstract

Vehicle wheel (1) comprising an electric motor (10) and a magnetic brake (20) extending into one another, one of the stator or rotor of the electric motor being common with one of the stator or rotor of the magnetic brake, respectively. Corresponding landing gear and aircraft. ABBREVIATED FIGURE: Fig. 2

Description

Title of the invention: Vehicle wheel comprising a drive device and a braking device

[0001] The present invention relates to the braking and ground movement of a vehicle and, more particularly, a wheel comprising a braking device and a drive device.

[0002] BACKGROUND OF THE INVENTION

[0003] In the field of aviation, it is now planned to equip aircraft wheels with rotating drive components to allow aircraft to move on the ground without using their propulsion systems. It is also known to equip aircraft wheels with a brake designed to selectively slow down and stop said aircraft when they are moving on the ground. The brake is generally a friction brake, which requires the replacement of wear parts whose friction, during braking, generates particularly polluting dust particles.

[0004] However, in the case of electric vertical take-off and landing aircraft (eVTOL), the wheels are traditionally small (between 6 and 10 inches) so that it is very difficult to integrate both a drive unit and a brake.

[0005] Moreover, the landing gear of eVTOLs is generally fixed, that is, not mobile between a retracted and deployed position as is the case for larger aircraft. Increasing the size of the wheels to integrate a drive mechanism and a brake would therefore tend to increase the drag forces exerted on the landing gear during flight, and thus reduce the flight range of the eVTOL.

[0006] Climate change is a major concern for many legislative and regulatory bodies worldwide. Indeed, various restrictions on carbon emissions have been, are being, or will be adopted by various states. In particular, an ambitious standard applies to both new types of aircraft and those currently in operation, requiring the implementation of technological solutions to bring them into compliance with current regulations. Civil aviation has been actively working for several years now to contribute to the fight against climate change.

[0007] Technological research efforts have already led to very significant improvements in the environmental performance of aircraft. All stakeholders in the sector are constantly working to improve energy efficiency. The Applicant takes into account the factors impacting all phases of design and development to obtain less energy-intensive, more environmentally friendly aeronautical components and products whose integration and use in civil aviation have moderate environmental impacts with the aim of improving the energy efficiency of air transport.

[0008] Consequently, the Applicant is constantly working to reduce its climate impact by using methods and operating virtuous development and manufacturing processes that minimize greenhouse gas emissions to the minimum possible in order to reduce the environmental footprint of its activity.

[0009] This sustained research and development work focuses on new generations of aircraft engines, the weight reduction of aircraft, in particular through the materials used and lighter on-board equipment, the development of the use of electrical technologies to provide propulsion, and, as essential complements to technological progress, aviation biofuels.

[0010] SUBJECT OF THE INVENTION

[0011] The invention aims to provide a wheel integrating a drive device and a braking device making it possible to overcome at least in part the aforementioned disadvantages. Summary of the invention

[0012] For this purpose, according to the invention, a vehicle wheel, mounted for rotation on an axle, is provided, comprising: • an annular rim connected by a disc to a hub received to pivot on the axle, the rim delimiting with the hub an annular space closed by the disc; • a radial flux electric motor comprising a first stator and a first rotor arranged coaxially with the wheel to produce between them a first magnetic flux capable of generating a driving torque in rotation of the wheel; • a magnetic brake.

[0013] According to the invention, the electric motor and the magnetic brake extend into one another within the annular space,

[0014] the first rotor also serving as the rotor for the magnetic brake so as to produce with a stator of the magnetic brake a second magnetic flux capable of generating eddy currents generating a braking torque of the wheel, the stator of the magnetic brake being arranged coaxially with the wheel, or

[0015] the first stator also serving as a stator for the magnetic brake so as to produce with a rotor of the magnetic brake a second magnetic flux capable of generating eddy currents generating a braking torque of the wheel, the the rotor of the magnetic brake being arranged coaxially with the wheel.

[0016] This results in a radial superposition of the electric motor and the magnetic brake and even a partial fusion of the electric motor and the magnetic brake since the first rotor or the first stator of the electric motor also serves as an active element for the magnetic brake.

[0017] The electric motor and the magnetic brake are engaged with each other and occupy a relatively small volume.

[0018] This allows the integration of the electric motor and the magnetic brake inside the wheel without significantly increasing the drag forces opposing the movement of said wheel.

[0019] The invention thus makes it possible to associate with an aircraft wheel both an electric motor and a magnetic brake even if the wheel is small in size.

[0020] The mass of the assembly formed by the electric motor and the magnetic brake is thus relatively low.

[0021] Furthermore, ground maintenance operations are thus simplified.

[0022] It is advantageously noted that with the invention it is not necessary to equip the wheel with an actuation system enabling it to switch from the function of the electric motor to that of the magnetic brake.

[0023] Optionally, one of the first or second rotor is adjacent to the rim and the other of the first rotor and the second rotor is adjacent to the hub, the first stator and the second stator extending between the first rotor and the second rotor.

[0024] Optionally, the first stator and the second stator are radially opposite each other.

[0025] Optionally, the first stator extends inside the second stator.

[0026] Optionally, the first stator or the first rotor includes a Halbach network formed at least in part by electromagnets, the one in the first stator or the first rotor including the Halbach network being the one also serving as the stator, respectively as the rotor, for the magnetic brake.

[0027] Optionally, the first rotor includes permanent magnets and / or electromagnets capable of interacting with the electromagnets equipping the first stator.

[0028] Optionally, the Halbach network is formed by a succession of electromagnets extending circumferentially around the hub and / or extending axially along the hub.

[0029] Optionally, the magnetic brake is radial flux.

[0030] Optionally, the first stator is fixed to a support that is stationary with respect to the axle.

[0031] Optionally, the second rotor is formed by the rim made of electrically conductive material or is formed by a local coating disposed on a periphery internal to said rim, the coating being made of electrically conductive material.

[0032] The invention also relates to an aircraft landing gear comprising at least one wheel as mentioned above.

[0033] The invention also relates to an aircraft comprising at least one landing gear as described above. BRIEF DESCRIPTION OF DRAWINGS

[0034] The invention will be better understood in the light of the following description, which is purely illustrative and not limiting, and should be read in conjunction with the accompanying drawings, among which:

[0035] [Fig.1] [Fig.1] is a simplified representation of an aircraft comprising main landing gear each equipped with a wheel according to the invention;

[0036] [Fig.2] [Fig.2] is an axial cross-sectional view of one of the wheels of the aircraft illustrated in the [Fig.1], according to a first embodiment of the invention;

[0037] [Fig.3] [Fig.3] is a schematic diagram of the arrangement according to a section cross-section of the wheel illustrated in [Fig.2];

[0038] [Fig.4] [Fig.4] is a schematic diagram illustrating how a magnetic flux can drive or brake the wheel illustrated in [Fig.2];

[0039] [Fig. 5] [Fig. 5] is an axial cross-sectional view of one of the wheels of the aircraft illustrated in the [Fig.1], according to a second embodiment of the invention. DETAILED DESCRIPTION OF THE INVENTION

[0040] With reference to [Fig. 1], the invention is described in application to an electric vertical takeoff and landing (eVTOL) aircraft A. For flight, landing and takeoff, the aircraft A is equipped with at least one propulsion unit M.

[0041] The aircraft A comprises two main landers P, each having a leg J ​​having an upper end fixed to a structure S of the aircraft and, opposite, a lower end carrying a wheel 1 rotating about an axis X on an axle E. The landers P are here fixed, but the invention is applicable to retractable type landers, or even to another type of aircraft or another type of vehicle such as a land vehicle.

[0042] According to a first embodiment, illustrated in [Fig. 2], the wheel 1 comprises an annular rim 2 connected by a disc 3 to a hub 4 pivotally supported on the axle E by means of bearings 5, 6. The rim 2 extends coaxially around the hub 4 and, together with said hub 4, defines an annular space having one end at least partially closed by the disc 3 and, at the opposite end, an open end. The rim 2 and the hub 4 thus extend coaxially to the axis X.

[0043] The wheel 1 is said to be "motorized", that is to say, equipped with a drive device intended to move the aircraft A without using its propulsion systems when it- this is on the ground.

[0044] The drive device comprises a radial flux electric motor 10 having, in a manner known per se, a first fixed element or stator 11, and a first rotating moving element or rotor 12. The stator 11 and the rotor 12 each have a central axis coinciding with the X-axis (which is therefore the axis of rotation of the wheel 1). The stator 11 and the rotor 12 thus extend coaxially with the X-axis. The stator 11 and the rotor 12 thus extend coaxially with the rim 2 and the hub 4.

[0045] Furthermore, the rotor 12 extends radially with respect to the stator 11.

[0046] Optionally, the rotor 12 extends inside the stator 11.

[0047] The wheel also has a support 30 integral with the axle E. The support is, for example, shaped as a plate. The support extends, for example, coaxially with the hub 4.

[0048] Optionally, the stator 11 is fixedly mounted on the support 30. The stator 11 is thus immobile with respect to the support 30 and therefore immobile with respect to the axle E.

[0049] The stator 11 here has the shape of a crown.

[0050] The stator 11 thus has an external circumferential face (forming a surface main external 11.1), an internal circumferential face (forming an internal main surface 11.2), a first lateral flank connecting the two circumferential faces and a second lateral flank (opposite to the first lateral flank and optionally parallel to the first lateral flank) connecting the other two circumferential faces.

[0051] The first lateral flank is the one fixed to the support 30 plan. The second lateral flank is opposite the disc 3. The main surface 11.1 is opposite the rim 2. The main surface 11.2 is opposite the rotor 12.

[0052] The rotor 12 is here in the form of a ring. The rotor 12 is here fixedly mounted on the disc 3, so that said rotor 12 is stationary with respect to the wheel 1. The rotor 12 comprises a series of permanent magnets (not shown). The permanent magnets are, for example, arranged so as to present an alternation of north and south poles on the same main surface 12.1 of the rotor 12, a surface which is opposite the main surface 11.2 of the stator 11.

[0053] The wheel 1 is also said to be "braked", that is to say, equipped with a braking device intended to selectively slow down the aircraft A when it is on the ground.

[0054] The braking device includes a radial flux magnetic brake 20 and includes, in a manner known per se, a second fixed element or stator 21, and a second rotating movable element or rotor 22.

[0055] The stator 21 and the rotor 22 each have a central axis coinciding with the X axis of rotation of the wheel 1. The stator 21 and the rotor 22 extend coaxially to the hub 4.

[0056] The stator 21 is here formed directly by the stator 11 of the electric motor 10. By the We will now only talk about stator 11, which is also stator 21.

[0057] The stator 11 and the rotor 22 extend radially opposite each other. In the present case, the stator 11 extends inside the rotor 22.

[0058] The stator 11 comprises a series of electromagnets (not shown). The electromagnets are arranged to form a Halbach array.

[0059] For the purposes of this application, it is recalled that a Halbach array is a particular arrangement of aligned permanent magnets, which increases the magnetic field on one side of the alignment while almost completely eliminating the magnetic field on the other side of the alignment. This is obtained by rotating the orientations of the magnetic fields on the successive magnets of the alignment (for the same surface of the alignment, the arrangement of the permanent magnets is thus as follows: north pole on the left, north pole upwards, north pole on the right and north pole downwards; north pole on the left, north pole upwards, north pole on the right and north pole downwards, etc.).

[0060] In the present case, thanks to the arrangement of the stator 11, the electromagnets form both the main external surface 11.1 of the stator 11 and both the main internal surface 11.2 of the stator 11.

[0061] As schematically shown in [Fig. 3], on the main surface 11.1 of the stator 11, the electromagnets are arranged so as to find successively along the circumferential direction: - a north electromagnet 31 (i.e., the north pole of the electromagnet 31 is opposite the rotor 22 - we can thus deduce that the south pole of this same electromagnet 31 is opposite the rotor 12), - an electromagnet is 32 (i.e., the north pole of electromagnet 32 ​​is oriented to the right of the north pole of the north electromagnet 31), - a south electromagnet 33 (i.e., the north pole of the electromagnet 33 is opposite the rotor 12 - we can thus deduce that the south pole of this same electromagnet 33 is opposite the rotor 22), - a west electromagnet 34 (i.e., the north pole of electromagnet 34 is oriented to the left of the north pole of electromagnet 31),

[0062] this succession of four electromagnets continuing all around the stator 11.

[0063] The rotor 22 is formed directly by the rim 2. The rim 2 is, for example, made of an electrically conductive material (e.g., aluminum, steel, etc.). The rim 2 has an inner circumference defining a main surface 22.1 of the rotor 22, which is separated from the main surface 11.1 of the stator 11 by a predetermined air gap e. It is therefore understood that the rotor 22 is stationary relative to the wheel 1.

[0064] It is noted that the same stator is used for both the electric motor 10 and at both for the braking device 20: in service depending on the direction of flow of the current passing through the electromagnets, the stator 11 can in fact be used to drive the wheel 1 in rotation or to brake the same wheel 1.

[0065] It is understood that the air gaps between the stator 11 and the rotor 22, and between the stator 11 and the rotor 12, must remain small for both the electric motor 10 and the braking device 20 to operate efficiently. Since the rotor 22 is formed by the rim 2, it dictates the positioning of the stator 11 (relative to the air gap e), which in turn dictates the positioning of the rotor 12 (relative to the air gap e' existing between the rotor 12 and the stator 11). Thus, the rotor 12 is fixed to the disc 3 at a predetermined distance from the X-axis. In this case, the rotor 12 is closer to the stator 11 than to the axle E. The rotor 12 therefore defines, together with the axle E, an internal sub-volume that can accommodate one or more other elements (gearbox, sensor, etc.).

[0066] The permanent magnets of the rotor 12 are therefore capable of interacting with the electromagnets equipping the stator 11 to produce a first magnetic flux driving the rotor 12, and therefore the wheel 1, into rotation around the axis X. Indeed, when the electromagnets equipping the stator 11 are traversed by an electric current in a first direction of circulation, they generate magnetic fields sufficient to generate a driving torque in rotation of the hub 4, and therefore of the wheel 1, by interacting with the series of permanent magnets equipping the rotor 12.

[0067] Furthermore, the electromagnets of the stator 11 are arranged to produce a second magnetic flux generating eddy currents in the rim 2 when said electromagnets are traversed by an electric current in a second direction of circulation (opposite to the first direction of circulation) and the wheel 1 rotates around its axis X of rotation. Indeed, when the electromagnets equipping the stator 11 are traversed by an electric current, they generate eddy currents in the rotor 22 sufficient to generate a braking torque on said rotor 22, and therefore on the wheel 1.

[0068] With reference to [Fig. 4], the electromagnets of the stator 11 forming a Halbach array are arranged as follows: - for the first direction of current flow, maximize the share of the first magnetic flux 11 seen by the electric motor 10 and limit as much as possible (or even eliminate) the share of the first magnetic flux sent towards the rim; - for the second direction of current flow maximize the share of the second magnetic flux 12 seen by rim 2 and limit as much as possible (or even eliminate) the share of the second magnetic flux sent towards the electric motor 10.

[0069] Preferably, the stator 11 is configured so that for the second direction of circumference Due to the current variation, the Halbach network is fixed in position, meaning that the different poles of the electromagnets are not reversed when the magnetic brake 20 is used. Thus, during braking, only the magnitude of the second magnetic flux can vary (depending on the intensity of the electric current passing through the stator 11).

[0070] Preferably, the stator 11 is configured so that, for the first direction of current flow, the Halbach array is not fixed in position. Preferably, only the east and west electromagnets (located at the main surface 11.2 of the stator 11) remain fixed in position when the electric motor 10 is in use. Conversely, the north and south electromagnets (located at the main surface 11.2 of the stator 11) are electronically controlled so that they can be interchanged into south and north electromagnets, respectively, at regular intervals. Thus, not only can the magnitude of the first magnetic flux vary (depending on the intensity of the electric current flowing through the stator 11), but also its direction. It is therefore possible to induce a relative rotational movement between the rotor 12 and the stator 11 by controlling the north and south electromagnets.

[0071] The electric motor 10 and the magnetic brake 20 thus work independently of each other but using common elements.

[0072] This makes the electric motor 10 and magnetic brake 20 assembly particularly compact and lightweight. In particular, the electric motor 10 and the magnetic brake 20 extend entirely within the annular space defined by the wheel 1.

[0073] It should also be noted that using the rim 2 as a heat sink and eddy current conductor helps to make this assembly more compact and lighter.

[0074] Furthermore, because the electric motor 10 and the magnetic brake 20 extend entirely within the annular space defined by the wheel 1, the drag forces exerted on the lander P are limited, especially since said lander P is not retractable. Such an arrangement of the electric motor 10 and the magnetic brake 20 thus limits the aerodynamic impact of the lander P.

[0075] It should also be noted that such an arrangement of the electric motor 10 and the magnetic brake 20 simplifies the integration of a drive device and a braking device while maintaining adequate performance.

[0076] With reference to [Fig. 5], a second embodiment will now be described.

[0077] The second embodiment is identical to the first embodiment except that the rotor 12 is not fixedly mounted to the disc 3 but is fixedly mounted on an outer circumference 36 of the hub 4. The outer circumference 36 of the hub 4 extends coaxially to the axle E and / or the axis X. The outer circumference 36 of the hub 4 thus extends radially with respect to the rotor 12.

[0078] It is therefore understood that the rotor 12 is stationary with respect to the wheel 1.

[0079] In order to maintain sufficiently low air gap values ​​e and e' so that the braking device and the motor 10 can function correctly, the rotor 12 can be directly fixed to the hub 4 or can be fixed to the hub 4 via an additional part 37.

[0080] Of course, the invention is not limited to the embodiments described but encompasses any variant falling within the scope of the invention as defined by the claims.

[0081] The wheel 1 may have a different structure from that described. The rim 2 of the wheel 1 may, for example, be formed from two half-rims, be made in a single piece, be produced by casting or by additive manufacturing...

[0082] Other materials than those indicated may be used.

[0083] Although the rim 2 here forms the rotor 22 of the magnetic brake 20, its inner circumference may also be provided with a local coating suitable for forming said rotor 22 (for example, copper, aluminum, silver, nickel, etc.). The rim 2 may then be made of a material different from that of the coating.

[0084] The stator 11 may not be mounted fixed to the axle E (directly or via a support) but may be mounted fixed to another part of the aircraft such as to one of its landing gears (either directly or via a support).

[0085] The arrangement of the electric motor 10 and the magnetic brake 20 can be reversed. In other words, the stator 11 and the rotor 12 of the electric motor 10 can respectively take the place of the stator 21 and the rotor 22 of the magnetic brake 20, and vice versa.

[0086] Permanent magnets can be carried by the stator 11 instead of the rotor 12. Electromagnets can be carried by the rotor 22 instead of the stator 21. It is therefore understood that the rotors 12 and 22 of respectively the electric motor 10 and the braking device 20 are then combined and the stators 11 and 21 are distinct.

[0087] The drive device may further include a reducer to increase the drive torque delivered to the wheel 1 by the electric motor 10. The reducer can be of any type: planetary reducer, wave reducer, cycloidal reducer, etc. Such a reducer can thus be arranged between the rotor 12 and the wheel 1. For example, the rotor 12 can be fixedly mounted to the reducer, which will itself be fixedly mounted to the disc 3 and / or the hub 4. For example, the reducer can thus be the additional part 37 shown in [Fig. 5].

[0088] Although the rotor 12 of the electric motor 10 here comprises only permanent magnets, for example to form a synchronous motor, it can also comprise electromagnets, for example to form an asynchronous motor. That the rotor 12 carrying electromagnets and / or permanent magnets, said electromagnets and / or said permanent magnets may optionally be arranged so as to form or not a Halbach lattice.

[0089] Although the stator 21 of the magnetic brake 20 here comprises only electromagnets, it may also comprise permanent magnets. In particular, the electromagnets and permanent magnets of the magnetic brake 20 may be arranged to form a Halbach array such that (for the main surfaces of the stator 21) the permanent magnets have an alternation of north and south poles, and the electromagnets have an alternation of east and west poles, with one magnet succeeding an electromagnet in at least one circumferential direction and / or an axial direction.

[0090] Although the rotor 22 of the magnetic brake 20 is here formed by the rim 2 or by a local coating disposed on the inner perimeter of said rim 2, it can also be formed by any element attached directly or indirectly to the rim 2.

[0091] The arrangement and number of bearings 5, 6 enabling the rotation of the wheel 1 around the axis X may be different from those described and illustrated.

[0092] At least one bearing can be arranged between the rim 2 and the support 30 and / or the stator 11. For example, at least one bearing can be arranged between the rim 2 and the support 30 and / or the stator 11 so as to guarantee a constant air gap e between the main surface 11.1 of the stator 11 and the main surface 22.1 of the rotor 22 so that the braking torque exerted by the magnetic brake 20 is constant (the braking torque being, in a way known per se, a function of the air gap e).

[0093] At least one bearing can be arranged between the stator 11 and the rotor 12. For example, at least one bearing can be arranged between the stator 11 and the rotor 12 so as to guarantee a constant air gap e' between the main surface 11.2 of the stator 11 and the main surface 12.1 of the rotor 12 so that the torque exerted by the electric motor 10 is constant (the torque being, in a way known per se, a function of the air gap e').

[0094] The number of stators (11, 21) and / or rotors (12, 22) may be different from those described.

[0095] The invention is applicable to other types of eddy current brakes, in particular axial flux or combining axial flux with radial flux.

[0096] The invention is usable on any type of vehicle, aerial (aircraft, airplane, helicopter, UAM, eVTOL ...) or terrestrial or amphibious.

[0097] The invention is usable for applications other than a vehicle and for example for any industrial or personal equipment requiring braking.

[0098] Although here the stator ring is formed of a single ring of electromagnets (the electromagnets extending successively in the circumferential direction in the following order: north electromagnet, east electromagnet, south electromagnet, west), the stator ring may be formed of at least two rings of electromagnets extending successively along the X axis (knowing that for each ring the electromagnets then extend successively along the circumferential direction in the following order: north electromagnet, east electromagnet, south electromagnet, west electromagnet).

Claims

Claims

1. Vehicle wheel (1), rotatably mounted on an axle (E), comprising: • an annular rim (2) connected by a web (3) to a hub (4) pivotally received on the axle, the rim delimiting with the hub an annular space closed by the web; • a radial flux electric motor (10) comprising a first stator (11) and a first rotor (12) arranged coaxially with the wheel to produce between them a first magnetic flux capable of generating a torque for driving the wheel in rotation; • a magnetic brake (20);characterized in that the electric motor and the magnetic brake extend into each other inside the annular space, the first rotor also serving as a rotor for the magnetic brake so as to produce with a stator of the magnetic brake a second magnetic flux capable of generating eddy currents generating a braking torque of the wheel, the stator of the magnetic brake being thus arranged coaxially with the wheel, or the first stator also serving as a stator for the magnetic brake so as to produce with a rotor of the magnetic brake a second magnetic flux capable of generating eddy currents generating a braking torque of the wheel, the rotor of the magnetic brake being thus arranged coaxially with the wheel.;

2. A wheel according to claim 1, wherein one of the first or second rotor is adjacent to the rim (2) and the other of the first rotor and the second rotor is adjacent to the hub (4), the first stator (11) and the second stator (21) extending between the first rotor (12) and the second rotor (22).

3. Wheel (1) according to claim 1 or claim 2, wherein the first stator (11) and the second stator (21) are radially opposite each other.

4. Wheel (1) according to claim 3, wherein the first stator (11) extends inside the second stator (21).

5. Wheel (1) according to one of the preceding claims, in which the first stator (11) or the first rotor (12) comprises a network of Halbach formed at least in part by electromagnets, that of the first stator (11) or of the first rotor (12) comprising the Halbach network being that also serving as stator, respectively rotor, for the magnetic brake.

6. Wheel (1) according to claim 5, in which the first rotor (12) comprises permanent magnets and / or electromagnets capable of interacting with the electromagnets equipping the first stator (11).

7. Wheel (1) according to claim 5 or claim 6, in which the Halbach network is formed by a succession of electromagnets extending circumferentially around the hub (4) and / or extending axially along the hub (4).

8. Wheel (1) according to one of the preceding claims, in which the second rotor (22) is formed by the rim (2) made of electrically conductive material or is formed by a local coating arranged on an internal periphery of said rim (2), the coating being made of electrically conductive material.

9. Landing gear (P) of an aircraft (A) comprising at least one wheel (1) according to any one of the preceding claims.

10. Aircraft (A) comprising at least one landing gear (P) according to claim 9.

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